The present invention relates to a balancer device for reducing secondary vibration caused by rotation of an internal combustion engine.
Hereinafter, the terms “upper”, “lower”, “above”, “below” and the like are used with respect to the direction of gravity; and the terms “front” and “rear” are used with respect to the orientation of a vehicle to which an internal combustion engine with a balancer device is mounted.
Japanese Patent No. 5186424 discloses a balancer device for reducing secondary vibration in an internal combustion engine, which includes a housing fixed to the internal combustion engine, a roller bearing disposed in the housing, a balancer shaft rotatably supported in the housing by the roller bearing, a balancer weight integrally mounted on the balancer shaft and rotatably accommodated in an weight accommodation space of the housing and a gear fitted around the balancer shaft and rotatably accommodated in a gear accommodation space of the housing. In this balancer device, an oil introduction hole is formed in an upper side of the gear accommodation space for introduction of oil from the internal combustion engine into the gear accommodation space. Further, the gear accommodation space is arranged such that a lateral side of the gear accommodation space faces an axial end portion of the roller bearing. When the gear is rotated with rotation of the balancer shaft, the oil in the gear accommodation space is agitated by external teeth of the gear so as to create an atmosphere of oil mist or splash in the gear accommodation space. The roller bearing is lubricated by such oil mist or splash from the gear accommodation space.